Core for hollow concrete structures.



R, B. HARTMAN.

GORE FOR HOLLOW CONCRETE STRUCTURES.

APPLIOATION FILED AUG. 24, 1909.

Patented July 30, 1912.

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El vi tn zones COLUMBIA PLANOGRAPH Lu WASHINGTON, D. c.

RUDOLPH B. HARTIVIAN, OF MILWAUKEE, WISCONSIN.

GORE FOB HOLLOVI CONCRETE STRUCTURES.

Application filed August 24, 1909.

To all whom it may concern:

Be it known that I, RUDOLPH B. HART- MAN, of Milwaukee, V'Visconsin,have invented a Core for Hollow Concrete Structures, of which thefollowing is a specification.

This invention relates to structural concrete work, and has to do withhollow or cored forms such as are found in columns, chimneys, walls,piers and the like; and the object of my invention is to provide asimple. cheap and easily constructed collapsi- The nature of myinvention will best be understood from a consideration of theaccompanying drawings illustrating the con struction thereof, whereinFigure 1 is a front elevation of the core} with the side-piece in frontbroken away on the right-hand side and the endpiece shown I in section.Fig. 2 is a side elevation there of. Fig. 3 is a plan-view thereof, partbeing broken away. Fig. t is a side view of an alternative form withnon-tapering enclpieces, and Fig. 5 is a separate view of one then readyto be set up again and reused of the spring-clips which may be used.

In these drawings every reference letter refers to the same part in eachfigure.

The four main elements of the core are the two end-pieces, designated a,and the two side-pieces, designated Z). Said endpieces may be in theform of bars of any desired shape and may be made with a taper as shownin Figs. 1 to 3, or of uniform section as shown at a in Fig. 4;. The

former is the most desirable, the latter the simpler form. Ordinarily itwill be found convenient to use gas-pipes or hollow tubular elements oflike nature to form the endpieces, as shown in the drawings; but it isnot necessary that said end-pieces should be tubular, or that theyshould be of circular section. At their upper ends, means are providedsuch as holes 0 for engaging them with a hook, bar or other grapplingdevice, whereby they are withdrawn endwise from the core after theconcrete has set.

The side-pieces b are in the form of plates,

Specification of Letters Patent.

the core is collapsed. after;

Patented July 3t 1912.

Serial No. 514,389.

preferably constructed of boards laid horizontally and secured togetherby battens (Z; said battens being set slightly with-in the ends of theboards so that they form seats or abutnients for the end-pieces a whenthe ends of the board rest on the sides of the end-pieces; thus holdingthe end-pieces against inward displacement, as illustrated in Figs. 1 to3.

In setting up the core, the side-plates b are temporarily held togetherby cleats c, at top and bottom, at the proper spacing to allow theend-pieces to fit snugly between them; then the latter are secured inposi tion by means of straps or wires 5/ extending around them andsecured at each end to a nail h or other appropriate fastening. Ifpreferred, instead of the straps or wires 9, spring-clips 2' may beused, shown in detail in Fig. 5, said clips holding the four partstogether withoutnecessitating the cleats c and If preferred, instead ofor in addition to the upper cleats 7, a plank j may be used to cover theopen face of the core and prevent rubbish, tools, and other objects fromfalling in.

After the concrete is poured around the core, the latter is removed bysimply withdrawing the end-pieces a endwise, leaving the side-pieces 5free, and these latter can then be readily removed, leaving the strapsor wires 9 and the clips 2' in the concrete if they fail to come outreadily. The core is in another place. It is to be observed that whilethe taper-form of piece a is theoretically the more correct as providinga certain amount of lateral draft in addition to the end draft given bytapering the sidepieces Z), in practice this is not found necessary as ageneral rule, and nontapering pieces, especially if they are iron pipes,are used as being the cheapest and the most generally available.

Various changes and modifications in the constructions as herein shownmay be made without departing from the spirit of my invention, and IWish it understood therefore that the latter is not otherwise limitedthan by the reasonable scope of my claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A collapsible core for hollow concrete structures comprising, incombination, a pair of bar-shaped end-pieces, a pair of plateshapedside-pieces each consisting of a plurality of transverse planks unitedby longitudinal battens, the ends of said planks resting againstopposite sides of said end-pieces and said battens being set at apredetermined distance within the ends of said planks and formingabutments for said endpieces to prevent inward displacement thereof; andmeans for holding said end-pieces against outward movement.

2. A collapsible core for hollow concrete structures comprising, incombination, a pair of bar-shaped end-pieces, a pair of plateshapedside-pieces each consisting of a plurality of transverse planks unitedby longitudinal battens, the ends of said planks resting againstopposite sides of said end-pieces and said battens being set at apredetermined distance within the ends of said planks and formingabutments for said enclpieces to prevent inward displacement thereof;and a number of bands passing around said end-pieces and having theirends engaging said side-pieces.

3. A collapsible core for hollow concrete structures comprising, incombination, a pair of bar-shaped end-pieces a pair of plateshapedside-pieces each consisting of a plu rality of transverse planks unitedby longitudinal battens, the ends of said planks resting againstopposite sides of said end-pieces and said battens being set at apredetermined distance within the ends of said planks and formingabutments for said endpieces to prevent inward displacement thereof; anda number of bands having their ends secured to said side-pieces andpassing around said end-pieces to hold them against outwarddisplacement.

4. A collapsible core for hollow concrete structures comprising, incombination, a pair of bar-shaped end-pieces of circular crosssectionforming and closing the ends and a pair of longitudinally tapered plateseach composed of a plurality of transverse members forming the sides andabutting at their end edges upon said end-pieces.

5. A collapsible core for hollow concrete structures, comprising incombination, a pair of end members substantially circular in crosssection, a pair of flat plates each of a plurality of transverselydisposed members the end edges whereof rest on opposite sides of saidend members and form therewith a Copies of this patent may be obtainedfor 7. A collapsible core for hollow concrete structures comprising, incombination, a pair of downwardly taperlng tubular end-pleces, a pair ofdownwardly tapering plate-shaped side-pieces, the ends of saidside-pieces resting on opposite faces of said end-pieces, abutments onsaid side-pieces adapted to hold said end-pieces against inwarddisplacement, means for connecting said sidepieces for holding them inposition against said end-pieces, and means secured to said side-piecesand passing around said end pieces for preventing outward displacementof the latter.

8. A collapsible core for hollow concrete structures comprising a pairof side-plates each having disposed vertically on its inner face andnear but slightly within the opposite side-edges a pair of longitudinalstrips; and a pair of end-pieces of circular crosssection which areadapted to abut against the outer edges of said strips and the innerface of the side-edges of said plates; thereby closing the intervalbetween the side-plates.

9. A collapsible core for hollow concrete structures comprising a pairof side-plates each having disposed vertically on its inner face andnear but slightly within the opposite side-edges a pair of longitudinalstrips; and a pair "of downwardly tapering endpieces of circularcross-section which are adapted to'abut against the outer edges of saidstrips and the inner face of the sideedges of said plates; therebyclosing the in terval' between the side-plates. I I In witness whereof,I have hereuntos'e my hand this 22nd day of April, 1909. f

RUDOLPH B. HARTMAN: Witnesses:

GEORGE W. OoLLEY, O. ON EH1.

five cents each, by addressing the Commissioner of Patents, Washington,D. c. v

